fuzz: yet another attempt to deal with mkdtemp() failures. (envoyprox…

…y#4228)

Still more failures overnight.

1. Avoid doing mkdtemp() more than once per fuzz run.

2. Make sure we pickup failures in RELEASE_ASSERT line, we were losing messages in truncated logs on
   ClusterFuzz.

3. Use C++ level std::filesystem for directory creation for each fuzz test case.

Hopefully this stabilizes or makes it clearer what is failing on ClusterFuzz.

Risk level: Low
Testing: bazel and oss-fuzz Docker server_fuzz_test.

Signed-off-by: Harvey Tuch <htuch@google.com>

test/fuzz/fuzz_runner.cc

@@ -12,19 +12,12 @@ namespace Fuzz {
 
 spdlog::level::level_enum Runner::log_level_;
 
+uint32_t PerTestEnvironment::test_num_;
+
 PerTestEnvironment::PerTestEnvironment()
-    : test_tmpdir_([] {
-        static uint32_t test_num;
-        const std::string fuzz_path =
-            TestEnvironment::temporaryPath(fmt::format("fuzz_{}.XXXXXX", test_num++));
-        char test_tmpdir[fuzz_path.size() + 1];
-        StringUtil::strlcpy(test_tmpdir, fuzz_path.data(), fuzz_path.size() + 1);
-        if (::mkdtemp(test_tmpdir) == nullptr) {
-          ENVOY_LOG_MISC(critical, "Failed to create tmpdir {} {}", fuzz_path, strerror(errno));
-          RELEASE_ASSERT(false, "");
-        }
-        return std::string(test_tmpdir);
-      }()) {}
+    : test_tmpdir_(TestEnvironment::temporaryPath(fmt::format("fuzz_{}", test_num_++))) {
+  TestEnvironment::createPath(test_tmpdir_);
+}
 
 void Runner::setupEnvironment(int argc, char** argv, spdlog::level::level_enum default_log_level) {
   Event::Libevent::Global::initialize();

test/fuzz/fuzz_runner.h

@@ -21,6 +21,7 @@ class PerTestEnvironment {
   std::string temporaryPath(const std::string& path) const { return test_tmpdir_ + "/" + path; }
 
 private:
+  static uint32_t test_num_;
   const std::string test_tmpdir_;
 };
 

test/test_common/environment.cc

@@ -29,19 +29,6 @@
 namespace Envoy {
 namespace {
 
-// Create the parent directory of a given filesystem path.
-void createParentPath(const std::string& path) {
-#ifdef __APPLE__
-  // No support in Clang OS X libc++ today for std::filesystem.
-  RELEASE_ASSERT(::system(("mkdir -p $(dirname " + path + ")").c_str()) == 0, "");
-#else
-  // We don't want to rely on mkdir etc. if we can avoid it, since it might not
-  // exist in some environments such as ClusterFuzz.
-  std::experimental::filesystem::create_directories(
-      std::experimental::filesystem::path(path).parent_path());
-#endif
-}
-
 std::string getOrCreateUnixDomainSocketDirectory() {
   const char* path = ::getenv("TEST_UDSDIR");
   if (path != nullptr) {
@@ -62,7 +49,10 @@ std::string getTemporaryDirectory() {
   if (::getenv("TMPDIR")) {
     return TestEnvironment::getCheckedEnvVar("TMPDIR");
   }
-  return "/tmp";
+  char test_tmpdir[] = "/tmp/envoy_test_tmp.XXXXXX";
+  RELEASE_ASSERT(::mkdtemp(test_tmpdir) != nullptr,
+                 fmt::format("Failed to create tmpdir {} {}", test_tmpdir, strerror(errno)));
+  return std::string(test_tmpdir);
 }
 
 // Allow initializeOptions() to remember CLI args for getOptions().
@@ -71,6 +61,28 @@ char** argv_;
 
 } // namespace
 
+void TestEnvironment::createPath(const std::string& path) {
+#ifdef __APPLE__
+  // No support in Clang OS X libc++ today for std::filesystem.
+  RELEASE_ASSERT(::system(("mkdir -p " + path).c_str()) == 0, "");
+#else
+  // We don't want to rely on mkdir etc. if we can avoid it, since it might not
+  // exist in some environments such as ClusterFuzz.
+  std::experimental::filesystem::create_directories(std::experimental::filesystem::path(path));
+#endif
+}
+
+void TestEnvironment::createParentPath(const std::string& path) {
+#ifdef __APPLE__
+  // No support in Clang OS X libc++ today for std::filesystem.
+  RELEASE_ASSERT(::system(("mkdir -p $(dirname " + path + ")").c_str()) == 0, "");
+#else
+  // We don't want to rely on mkdir etc. if we can avoid it, since it might not
+  // exist in some environments such as ClusterFuzz.
+  std::experimental::filesystem::create_directories(
+      std::experimental::filesystem::path(path).parent_path());
+#endif
+}
 absl::optional<std::string> TestEnvironment::getOptionalEnvVar(const std::string& var) {
   const char* path = ::getenv(var.c_str());
   if (path == nullptr) {

test/test_common/environment.h

@@ -175,5 +175,17 @@ class TestEnvironment {
    * @return string the contents of the file.
    */
   static std::string readFileToStringForTest(const std::string& filename);
+
+  /**
+   * Create a path on the filesystem (mkdir -p ... equivalent).
+   * @param path.
+   */
+  static void createPath(const std::string& path);
+
+  /**
+   * Create a parent path on the filesystem (mkdir -p $(dirname ...) equivalent).
+   * @param path.
+   */
+  static void createParentPath(const std::string& path);
 };
 } // namespace Envoy